The purpose of this project was to study the local viscoelastic properties of the intimal layer of large arteries with a view towards understanding their role in atherogenesis. The strength of the endothelium was studied by exposing the endothelial surface to a saline jet of known strength and quantifying the resulting damage to the endothelial cells. The compliance of the intimal layer was studied by exposing the surface to a microindentor and measuring the identation of the intimal surface as a function of applied force. These studies will shed added light on the role of mechanical factors in the pathogenesis of atherosclerosis. BIBLIOGRAPHIC REFERENCES: Patel, D.J., R.N. Vaishnav. Mechanical properties of arteries. Cardiovascular Flow Dynamics and Measurements. edited by Ned H. Hwang and Nils A. Normann. University Park Press. Baltimore. 1977. pp. 439-472. Young, J.T., R.N. Vaishnav, D.J. Patel. Nonlinear anisotropic viscoelastic properties of canine arterial segments. J. of Biomechanics. 1977 (In press).